which yet is readily accorded to him by many of the disputants themselves. The case is not rendered any clearer by the fact that some of those writers who have attempted to influence public opinion on the subject have no very exact ideas as to what the tenets of the rival leaders really are. From the beginning of the controversy about development which was started by the appearance of the Origin of Species in 1859, views have been constantly attributed to Darwin which he did not hold, and similar misrepresentations with regard to his position and that of other leaders of scientific thought are almost equally current at the present day.

The discussions that have just been alluded to are of more than merely academic interest, for the points round which they centre have a real bearing on the application of evolutionary ideas, not only to biological questions, but also to problems of social and religious importance. In view of these circumstances it may not be amiss to trace in a few words the history of the theory of organic evolution, and to state, so far as may be possible, the nature of the contributions made by some of the leading exponents of that theory to the common stock. It would clearly be unsuitable to enter in these pages into a detailed discussion of the various points at issue between the rival schools. All that will be here attempted is a short account, as free as may be from technicalities, of the steps by which the doctrine of evolution has won its way to general acceptance, and of the divergencies as to methods which still exist between those who are agreed as to the result. For our present purpose there is no need to dwell on the developmental

A different impression is given by a pas nage from Aristotle's "Physic. Auscult." (II. 8, 11.), as translated in the "Historical Sketch" prefixed to the later editions of the

views of the earlier philosophers. The main idea of organic evolution was familiar to Empedocles and to Aris totle. The germs of a theory of natural selection are to be found in the fragments of the former philosopher; and the same speculation is canvassed by Aristotle, who, however, prefers to explain adaptations by an innate tendency towards perfection—a principle, in fact, somewhat resembling what the late Professor Eimer meant by orthogenesis.1

Lucretius, saturated as he was with the atomistic view of nature, had yet, like his master Epicurus, an inkling of the principle of the "survival of the fittest." Among Christian philoso; phers of the Middle Ages we find a distinct disposition to acquiesce in the Greek idea of derivation, along with a counter-view more nearly in favor of what we now understand by "special creation." A well known passage of St. Thomas Aquinas puts the case as follows:

As to the production of plants, Augustine holds a different view. For some expositors say that, on this third day [of creation] plants were actually produced each in his kind-a view which is favored by a superficial reading of the letter of Scripture (secundum quod superficies literae sonat). But Augustine says that the earth is then said to have brought forth grass and trees causaliter-i.e. it then received the power to produce them. This view he confirms by the authority of Scripture, which says, "These are the generations of the heaven and of the earth, when they were created, in the day that the Lord God made the earth and the heavens, and every plant of the field before it was in the earth, and every herb of the field before it grew."-Gen. ii. 4. Before, then, they came into being on the earth they were made causally in the earth. And this is confirmed by reason. For in those

"Origin of Species." But it seems clear that the drift of Aristotle's argument has here been misunderstood by both Darwin and the trans

lator.

first days God made creatures primarily or causaliter, and then rested from His work, and yet after that, by His superintendence of things created, He works even to this day in the work of propagation. For the production of plants from the earth belongs to the work of propagation.

Here, as Aubrey Moore hàs well pointed out, "though there is no idea of the method by which the 'kinds' were brought forth from the earth, or of their inter-relations with one another, nothing of what we should call a scientific account, there is a clear conception of creation by growth or evolution, which is quite contrary to what is known as special creation." And it is not without justice that Osborn declares that

if the orthodoxy of Augustine had remained the teaching of the Church, the final establishment of Evolution would have come far earlier than it did, certainly during the eighteenth instead of the nineteenth century, and the bitter controversy over this truth of Nature would never have arisen.

No doubt it would have been well for the cause of scientific progress if the more elastic views of creation professed by St. Augustine, and at least uncondemned by St. Thomas, had prevailed. That they did not do so in the seventeenth and eighteenth centuries cannot, however, be laid exclusively to the charge of the Church. The truth of the matter is that until the scientific idea of "species" acquired form and distinctness there could be no dogma of "special" creation in the modern sense. This form and distinctness it did not possess until the naturalists of the seventeenth century began to substitute exactness of definition for the previous vague characterizations of the objects of nature. As the notion of strictly defined and interrelated groups began to take shape, the terms "genus" and "spe

cies," borrowed from the logicians. were used in a quasi-technical sense to give greater precision to the new scientific conception. The definition and description of well known and of fresh "species" proved to be a most attractive pursuit for naturalists from the days of Ray and Willughby onwards; the conviction of the reality and permanence of the groups thus established gradually strengthened; and at last we find Linnæus proclaiming that just so many "species" exist as there were diverse forms produced by the Creator in the beginning. This view of the reality and fixity of species perhaps marks a necessary stage in the progress of scientific inquiry. An accurate nomenclature of the forms of life was felt to be essential, and the natural result of the labors of systematists was to exalt the importance of strict definition, to encourage the rigid view of "species," and to crystallize, as it were, the notion of the order and permanence of the various forms of life which were now for the first time examined and classified with scientific accuracy. There has been no more

positive upholder of the doctrine of /fixity of species than Cuvier, but it is most significant to find in one of Lyell's letters to Darwin the following statement of the great comparative anatomist's position:

Constant Prévost, a pupil of Cuvier forty years ago, told me his conviction "that Cuvier thought species not real, but that science could not advance without assuming that they were so." (March 1863).

We see, then, that when Cuvier brought into play all his immense authority and influence in order to oppose Lamarck and the transformists of his day, he was not giving effect to his own deeply-rooted conviction. He was only defending an assumption which he thought, mistakenly enough,

must be made in the interest of science. It is unnecessary to insist further upon this point, but we may urge, without fear of contradiction, that from the latter part of the seventeenth to the middle of the nineteenth century the bulk of scientific opinion was in favor of the reality and fixity of species.

It may be gathered from the passage above quoted from St. Thomas that, up to his day, there were among expositors of the Scriptures two distinct lines of interpretation of the Biblical account of creation, to neither of which could the Church be said to have committed herself. Coming

down to times more nearly approaching our own, we can scarcely wonder that as the scientific conception of species grew in importance and distinctness, the views of those who approached the subject of creation from the theological side should be influenced in the same direction, and should equally be led to favor the doctrine of fixity. Huxley, not without reason, adduces Milton's account of creation as giving far less equivocal expression to the theory of special creation than does the text of Genesis. Osborn seems to be struck with surprise that the Jesuit Suarez pronounced positively for special creation "so late as the seventeenth century." It is perhaps rather a matter for remark that the new scientific doctrine should have influenced theological -opinion so early.' However, there is no doubt that under this kind of influence, and under the gradual discrediting of the Aristotelian tenet of : spontaneous generation, the liberal views of creation represented by St. Augustine underwent for the time a total eclipse in the minds of theologians; and a theory which, in its Linnæan dress, would have seemed as

It is fair to state that this interpretation of Suares has been questioned.

strange and perhaps as unintelligible to St. Thomas Aquinas as it would to Francis Bacon, came to hold the field in theology and science alike.

But although the old transformist speculations had become unpopular, the eighteenth century was not allowed to pass without some protest against the received scientific view. Buffon, if left to himself, might have preferred, in modern parlance, to "sit on the fence," or even to declare for development. As it was, he came down on the side of the fixity of species, probably under pressure. Erasmus Darwin was a man of different mould. His writings show him to have been a convinced upholder of the principle of specific transmutation, though his views of evolutionary method were often extravagant. But he stood to his guns, in spite of much adverse criticism which not infrequently took the form of ridicule.

Passing over Goethe and Oken, by both of whom the general idea of organic evolution was accepted, we may remark that Geoffrey St. Hilaire, according to his son Isidore, had already in the year 1795 formed the opinion in favor of the transmutation of species which he was to publish about thirty years later.

But the most famous name among evolutionists of this period is undoubtedly that of Lamarck. Opinions will differ as to the importance to be assigned in the history of evolutionary doctrine to the great French naturalist, but there is no doubt that, if not the first to conceive of organic development on a large scale, he was the first to carry out the principle into elaborate detail, and to attempt the construction of a rational "phylogeny" or genealogical tree of the animal kingdom. Lamarck held that the origin of new organs in animals was due to the efforts or movements initiated

by new needs or wants; that every organ was developed by use and tended to diminish and disappear under disuse; finally, that every trait acquired in the organization of individuals ("tout ce qui a été acquis, tracé ou changé dans l'organisation des individus") during life is preserved by generation and transmitted to new individuals which are produced by the former. These are the true "Lamarckian factors" so often referred to in the current literature of evolution; they may be summed up in the phrase "inherited effects of use and disuse." To these supposed causes of evolution is often added the direct effect of the environment, also assumed to be capable of hereditary transmission. Thus Romanes, in his Darwin and after Darwin, vol. il., writes as follows:

So far as we shall be concerned with them throughout this treatise, the Lamarckian factors consist in the supposed transmission of acquired characters, whether the latter be due to the direct influence of external conditions of life on the one hand, or to the inherited effects of use and disuse on the other.

Lamarck, however, denied that changes in the organization of the higher animals could be directly effected by the environment, though he admitted it in the case of the lower animals and of plants. In his view an alteration in the external conditions of life could only act on the higher animals indirectly, i.e. by calling forth new wants, which in their turn give rise to new efforts, new habits, and new forms of growth. The supposed transmission of the direct effects would be more justly associated with the name of Buffon. It is of the first importance to note that, whether the "Lamarckian factors" be understood in their wider or narrower

sense, the hereditary transmission of individually acquired characters is absolutely essential to their operation.

In the elaboration of his famous system Lamarck had given free rein to speculation. Such basis in the fields of observation and experiment as his theoretical fabric possessed was a narrow one, and quite inade quate for the burden it was called upon to bear. For this, and for other reasons, Lamarckism never made much way. It did not appeal to the scientific intelligence of the time, and its immediate effect was rather to encourage a reaction against the "scientific use of the imagination." We have seen what Cuvier's attitude was towards the exponents of transformism. Whatever his own secret suspicions as to the fixity of species may have been, he considered Lamarck and St. Hilaire as dangerous men, whose views and methods should be resisted in the cause of sober science. He therefore committed himself to what Osborn calls

It is not creditable to our claims of superior enlightenment that there are naturalists of standing at the present day who, without Cuvier's excuse, still reflect his obscurantist policy by both precept and example.

The publication in 1844 of the once celebrated Vestiges of Creation, the authorship of which, so far as we are aware, was never acknowledged, renewed in this country the interest in the subject of organic evolution, which had been somewhat dormant since the beginning of the century. But even before the appearance of this able work, which advocated the cause of progres

sive development with a zeal that was not in all respects according to knowledge, there were germinating in the mind of Charles Darwin the first suggestions of a theory which was to revolutionize the whole subject, and to bring about the presentment of the transformist views in such a shape as ultimately to command the assent of the whole scientific world. The his

tory of the joint publication in 1858 of the views of Darwin and Wallace has often been told. It is an honorable episode in the annals of science; but for our present purpose its chief interest lies in the fact that each of these acute and skilful naturalists failed to find a sufficient explanation of the evolutionary process in the views that had hitherto passed current, and that each of them came independently to the conclusion that the missing factor was the principle of natural selection. The note had been struck early in the history of Greek philosophy, but feebly and to little purpose. The question to be solved was, granted that species are not immutable, and that on the whole there has been a gradual process of develop ment in the world of organisms from the lower to the higher, granted also that adaptation to circumstances is the universal law of nature, how can this transformation and adaptation be explained in a reasonable manner? Previous attempts at answering the question had proved generally unconvincing. They had failed to show how the methods of evolution could be inferred from the known properties of living beings; they involved an appeal to principles which were far removed from the scientific plane, or they founded themselves on hypotheses of which there existed no shadow of proof. On the other hand, the new champions of evolution took their stand upon phenomena that were matters of common knowledge. It was undenia

ble that in the domain of organic nature, although in a general sense like produced like, there was yet a wide scope for individual variation between the offspring of the same parents. It was equally true that in almost every instance the number of offspring produced immensely exceeded those that could ultimately survive and produce fresh offspring in their turn. What determined the survival of a few and the disappearance of the rest? The facts necessarily implied some form of weeding out, or "selection." The well-ascertained phenomena of variation supplied material of differing quality and therefore of differing value in relation to the environment. Since all could not survive it was obviously to be expected that those whose individual properties showed least correspondence with external conditions should be the first victims; the fortunate survivors must form a new starting-point for further variations between which a fresh "selection" would in due course be made. Here was an explanation of progressive modification, of divergence of different forms from the same stock, of adaptation to the conditions of life, which had recourse simply to known facts and principles, and which made no appeal to such shadowy "laws" as that of an innate tendency towards perfection, or to such unproved and improbable hypotheses as the production of an organ, or of a member, as the result of the "wants" and consequent efforts of a long series of ancestors. The importation of this element of common sense into the question in course of time had its proper effect. The appearance of the Origin of Species marked a turning-point in the his tory of evolutionary doctrine. The firm foundation of observation and experiment on which Darwin based his results, the multitude of hitherto isolated facts which now for the first time found their explanation